55. A living thing, usually with one cell that has a nucleus and other cells
parts, is a
a. moneran.
b. virus.
c. protist.
d. fungus.
To determine the correct answer, let's break down the question and analyze each option:
a. Moneran - Monerans are now considered outdated taxonomically. Monerans were previously used to refer to organisms like bacteria, which are single-celled prokaryotes. However, the classification system has changed, and bacteria are now classified under different categories. Therefore, option a is not correct.
b. Virus - Viruses are considered non-living particles rather than living organisms. They cannot be classified as living as they do not have cells or cellular structures. Therefore, option b is not correct.
c. Protist - Protists are eukaryotic organisms, meaning they have a membrane-bound nucleus and other organelles within their cells. They can exist as single-celled organisms or as multicellular organisms. Therefore, option c could be the correct answer.
d. Fungus - Fungi are eukaryotic organisms, but most fungi are multicellular, except for a few unicellular fungi like yeast. While fungi are living organisms, they usually do not exist as single-celled organisms. Therefore, option d is not the most appropriate answer.
Based on the given options, the best answer would be c. protist, as protists are usually single-celled organisms with a nucleus and other cellular components.